Single chip USB packages with swivel cover

ABSTRACT

A low-profile Universal-Serial-Bus (USB) assembly includes a modular USB core component that is mounted into a swivel casing. The modular USB core component includes a PCBA in which all passive components and unpackaged IC chips are attached to a single side of a PCB opposite to the metal contacts. The IC chips (e.g., USB controller, flash memory) are attached to the PCB by wire bonding or other chip-on-board (COB) technique. The passive components are attached by conventional surface mount technology (SMT) techniques. The swivel casing includes a holder that is pivotably mounted into an external housing by way of a pivot pin. The pivot pin is either a separate structure that is inserted into holes formed in the holder and housing, or is integrally formed on the holder.

RELATED APPLICATIONS

This application is a continuation-in-part (CIP) of U.S. patentapplication for “Electronic Data Storage Medium with FingerprintVerification Capability”, U.S. application Ser. No. 11/624,667, filedJan. 18, 2007, which is a divisional of U.S. patent application for“Electronic Data Storage Medium with Fingerprint VerificationCapability”, U.S. application Ser. No. 09/478,720 filed Jan. 6, 2000,now U.S. Pat. No. 7,257,714.

This application is also a CIP of U.S. patent application for “MoldingMethods To Manufacture Single-Chip Chip-On-Board USB Device” U.S.application Ser. No. 11/773,830, filed Jul. 5, 2007, which is a CIP ofU.S. patent application for “Low-Profile USB Device”, U.S. applicationSer. No. 11/112,501, filed on Apr. 21, 2005.

FIELD OF THE INVENTION

This invention relates to portable electronic devices, and moreparticularly to portable electronic devices such as those that utilizethe Universal-Serial-Bus (USB) specification.

BACKGROUND OF THE INVENTION

In the past, confidential data files were stored in floppy disks or weredelivered via networks that require passwords or that use encryptioncoding for security. Confidential documents can be sent by adding safetyseals and impressions during delivering. However, the aforesaid areexposed to the risks of breaking of the passwords, encryption codes,safety seals and impressions, thereby resulting in unsecure transfer ofinformation.

More recently, there is an ongoing trend towards the use ofminiaturized, portable computer peripheral devices to store confidentialdata. In certain cases, such peripheral devices have been reduced to“pocket size”, meaning that they can literally be carried in a user'spocket in the same manner as a wallet or set of keys. One example ofparticular interest, in which context the present invention will bedescribed herein, is a “flash disk”, or “Universal Serial Bus (USB)flash drive”.

The proliferation of portable computer peripheral devices, such as USBflash drives, has made the production of USB flash drives very costsensitive. For example, there is currently a strong demand for highquality USB devices that are very low in cost. Accordingly, there is anever increasing need for computer peripheral devices that are reliableand inexpensive to produce.

What is needed is a portable computer peripheral device that overcomesthe problems associated with conventional structures. What isparticularly needed is a high quality USB device that has a very lowproduction cost.

SUMMARY OF THE INVENTION

The present invention is directed to high quality swivel-type,low-profile USB devices (or other electronic data storage medium) thatinclude an external case that is mounted or otherwise formed over amodular USB core component such that the modular USB core component isselectively exposed for access by a data terminal by way of a swivelcover. The modular USB component includes a card body (i.e., a printedcircuit board assembly (PCBA)) and a single-piece molded housing thatencases all passive components and integrated circuit (IC) components ofthe PCBA, which include a non-volatile memory device, a card readerinterface circuit and a processing unit (e.g., a USB controller) thatare implemented using one or more integrated circuit (IC) die(s) mountedon said card body. All of the components encased by the single-piecemolded housing are formed on a selected surface of the card body, andstandard USB metal contacts are disposed on an opposing surface that isexposed outside of the molded housing (i.e., the components are onlymounted on a side of the card body that is opposite to the metalcontacts). The swivel cover selectively protects the metal contacts ofmodular USB core component from contamination or from scratches byallowing a user to rotate the metal contacts under a cover wall when notin use. In accordance with an aspect of the present invention, theswivel cover utilizes a novel pivot pin having a unique stoppagemechanism that locks the USB memory card in either in opened position orin closed position.

According to an aspect of the invention, passive components are mountedonto the PCB using one or more standard surface mount technology (SMT)techniques, and one or more IC die (e.g., an USB controller IC die and aflash memory die) are mounted using chip-on-board (COB) techniques.During the SMT process, the SMT-packaged passive components (e.g.,capacitors, oscillators, and light emitting diodes) are mounted ontocontact pads disposed on the PCB, and then known solder reflowtechniques are utilized to connect leads of the passive components tothe contact pads. During the subsequent COB process, the IC dies aresecured onto the PCB using know die-bonding techniques, and thenelectrically connected to corresponding contact pads using, e.g., knownwire bonding techniques. After the COB process is completed, the housingis formed over the passive components and IC dies using plastic moldingtechniques. By combining SMT and COB manufacturing techniques to producemodular USB core components, the present invention provides severaladvantages over conventional manufacturing methods that utilize SMTtechniques only. First, by utilizing COB techniques to mount the USBcontroller and flash memory, the large PCB area typically taken up bySMT-packaged controllers and flash devices is dramatically reduced,thereby facilitating significant miniaturization of the resulting USBdevice footprint (i.e., providing a shorter device length and thinnerdevice width). Second, the IC die height is greatly reduced, therebyfacilitating stacked memory arrangements that greatly increase memorycapacity of the USB devices without increasing the USB device footprint.Further, overall manufacturing costs are reduced by utilizing unpackagedcontrollers and flash devices (i.e., by eliminating the cost associatedwith SMT-package normally provided on the controllers and flashdevices). Moreover, the molded housing provides greater moisture andwater resistance and higher impact force resistance than that achievedusing conventional manufacturing methods. Therefore, the combined COBand SMT method according to the present invention provides a lessexpensive and higher quality (i.e., more reliable) memory product with asmaller size than that possible using conventional SMT-onlymanufacturing methods.

According to an embodiment of the invention, a modular USB corecomponent utilizes a single-chip controller/flash die that includes botha controller circuit and one or more flash block mass storage circuitsthat are interconnected by a bus. The controller circuit includes aninput/output (I/O) interface circuit that facilitates sending andreceiving commands and data to/from a host, and a flash-memorycontroller that facilitates sending and receiving sends data over theinternal bus to/from the flash mass storage blocks. By combining thecontroller and flash memory circuits, external pins are not required,thereby further reducing the PCB area required for controller and flashmemory devices, thus facilitating further miniaturization of USB devicesformed in accordance with the present invention.

According to an aspect of the present invention, the modular USB corecomponent formed in the manner described above is disposed in a swivelhousing so as to form a swivel-type, low-profile USB assembly. Inparticular, the modular USB core component is mounted in an elongatedholder having a flange such that the metal contacts are disposed at anend that is opposite to the flange. The holder is then connected to anexternal (swivel) housing having opposing upper and lower (first andsecond) walls that are separated by an elongated gap. The flange of theholder is connected to the external housing such that the holder ispivotable between a closed position in which the holder is disposed inthe gap between the upper and lower walls of the external housing, andan open position in which the holder is disposed outside of the externalhousing. In the closed position, the metal contacts of the modular USBcore component are covered (protected) by a region of the upper wall,thereby preventing damage from scratching or contamination. In the openposition, the front end of the holder forms the plug portion of alow-profile USB device that can be plugged into a female USB socket suchthat the metal contacts of the modular USB core component are accessibleby a data terminal.

In a specific embodiment, the swivel-type, low-profile USB assemblyincludes a separately formed pivot pin that is fixedly connected to theholder and rotatably engaged in the pivot opening. The pivot pinincludes curved arms having at least one protruding bump that is biasedoutward by the curved arms. When the holder is in either of the close oropened positions, the protruding bumps engage corresponding notchesdefined in the circular edge of a pivot opening formed in the upper wallof the external housing so as to “lock” the holder into theclosed/opened position. When the holder is manually rotated between theopened and closed positions, the curved arms bend inward and theprotruding bumps slide along the circular edge of a pivot opening. Thepivot pin thus provides a unique stoppage mechanism that facilitatesconvenient use of the USB assembly.

In a specific embodiment, the pivot pin is integrally formed on theflange of the holder such that the pivot pin is movably biased into thepivot opening in either of the close or opened positions, and is pusheddownward into the flange when the holder is manually rotated between theopened and closed positions. A raised engagement structure (rib)extending between the pivot pin and the flange engages a correspondingnotch formed in the external housing when the holder is in the openedand closed positions, thereby forming another unique stoppage mechanism.The external housing is formed form a bent piece of elongated metal, andthe gap gradually decreases between the upper/lower walls such that aheight of the gap at the pivot pin end is narrower than a height of thegap adjacent to the end wall.

Thus, the present invention facilitates the production of low-cost,highly reliable, high capacity swivel-type USB apparatus havingaesthetic casing designs that easily and conveniently incorporate theshort, modular USB core component.

BRIEF DESCRIPTION OF THE DRAWINGS

These and other features, aspects and advantages of the presentinvention will become better understood with regard to the followingdescription, appended claims, and accompanying drawings, where:

FIG. 1 is a schematic circuit block diagram illustrating an electronicdata storage medium according an embodiment of the present invention;

FIGS. 2(A) and 2(B) are perspective top and cross sectional side viewsshowing an exemplary modular USB device according to an embodiment ofthe present invention;

FIG. 3 is a flow diagram showing a method for producing the modular USBdevice of FIGS. 2(A) and 2(B) according to another embodiment of thepresent invention;

FIGS. 4(A) and 4(B) are bottom and top perspective views showing a PCBpanel utilized in the method of FIG. 3;

FIG. 5 is a perspective view depicting a surface mount technology (SMT)process for mounting passive components on a PCB according to the methodof FIG. 3;

FIG. 6 is a top perspective views showing the PCB panel of FIG. 4(B)after the SMT process is completed;

FIG. 7 is a simplified perspective view showing a semiconductor waferincluding integrated circuits (ICs) utilized in the method of FIG. 3;

FIGS. 8(A), 8(B) and 8(C) are simplified cross-sectional side viewsdepicting a process of grinding and dicing the wafer of FIG. 7 toproduce IC dies;

FIG. 9 is a perspective view depicting a die bonding process utilized tomount the IC dies of FIG. 8(C) on a PCB according to the method of FIG.3;

FIG. 10 is a top perspective views showing the PCB panel of FIG. 4(B)after the die bonding process is completed;

FIG. 11 is a perspective view depicting a wire bonding process utilizedto connect the IC dies of FIG. 8(C) to corresponding contact padsdisposed on a PCB according to the method of FIG. 3;

FIG. 12 is a top perspective views showing the PCB panel of FIG. 4(B)after the wire bonding process is completed;

FIGS. 13(A) and 13(B) are simplified cross-sectional side viewsdepicting a molding process for forming a molded housing over the PCBpanel of FIG. 4(B) according to the method of FIG. 3;

FIG. 14 is a top perspective views showing the PCB panel of FIG. 4(B)after the molding process is completed;

FIG. 15 is simplified cross-sectional side view depicting a singulationprocess for separating the PCB panel of FIG. 4(B) into individual USBdevices according to the method of FIG. 3;

FIGS. 16(A) and 16(B) are bottom and top perspective views showing USBdevices after the singulation process of FIG. 3 is completed;

FIGS. 17(A) and 17(B) are bottom and top perspective views showing themodular USB device of FIG. 16(A) after a marking process is performed inaccordance with the method of FIG. 3;

FIG. 18 is simplified cross-sectional side view showing a modular USBdevice including stacked-memory according to another embodiment of thepresent invention;

FIG. 19 is simplified cross-sectional side view showing a single-chipmodular USB device according to another embodiment of the presentinvention;

FIG. 20 is a block diagram showing a flash microcontroller integratedcircuit die with flash mass storage blocks;

FIG. 21 is an exploded perspective view showing a USB assembly with amodular USB core component disposed in a housing a swivel mechanismaccording to another embodiment of the present invention;

FIGS. 22(A) and 22(B) are front perspective (closed) and frontperspective (opened) views showing the USB assembly of FIG. 21 in anassembled state;

FIGS. 23(A) and 23(B) are exploded perspective and front perspective(retracted) views showing a sub-assembly of the USB assembly of FIG. 21;

FIG. 24 is an exploded perspective view showing a final assembly stepfor producing the USB assembly of FIG. 21;

FIG. 25 is a perspective view showing a pivot pin utilized in the USBassembly of FIG. 21;

FIGS. 26(A) and 26(B) are partial top views showing a portion of thepivot pin engaged in a pivot opening during operation of the USBassembly of FIG. 21;

FIG. 27 is an exploded perspective view showing the USB assembly of FIG.21 as modified to include cover plates;

FIGS. 28(A) and 28(B) are closed and opened perspective views showingthe USB assembly of FIG. 27 after the cover plates are attached;

FIGS. 29(A) and 29(B) are exploded perspective and front perspectiveviews showing a USB sub-assembly according to another embodiment of thepresent invention;

FIG. 30 is an exploded perspective view showing the sub-assembly of FIG.29(B) during assembly with an external housing to form a USB assemblyaccording to another embodiment of the present invention; and

FIGS. 31(A) and 31(B) are closed and opened perspective views showingthe USB assembly of FIG. 30 after assembly is completed.

DETAILED DESCRIPTION OF THE DRAWINGS

The present invention relates to an improved method for manufacturingUSB devices, and in particular to USB assemblies manufactured by themethod. The following description is presented to enable one of ordinaryskill in the art to make and use the invention as provided in thecontext of a particular application and its requirements. As usedherein, the terms “upper”, “upwards”, “lower”, and “downward” areintended to provide relative positions for purposes of description, andare not intended to designate an absolute frame of reference. Variousmodifications to the preferred embodiment will be apparent to those withskill in the art, and the general principles defined herein may beapplied to other embodiments. Therefore, the present invention is notintended to be limited to the particular embodiments shown anddescribed, but is to be accorded the widest scope consistent with theprinciples and novel features herein disclosed.

Referring to FIG. 1, according to an embodiment of the presentinvention, an electronic data storage card 10 is adapted to be accessedby an external (host) computer 9 either via an optional card reader 12or other interface mechanism, and includes a card body 1, a processingunit 2, one or more flash memory devices 3, a fingerprint sensor 4, aninput/output interface circuit 5, an optional display unit 6, a powersource (e.g., battery) 7, and a function key set 8.

Flash memory device 3 is mounted on the card body 1, and stores in aknown manner therein a data file, a reference password, and fingerprintreference data obtained by scanning a fingerprint of a person authorizedto access the data file. The data file can be a picture file or a textfile.

The fingerprint sensor 4 is mounted on the card body 1, and is adaptedto scan a fingerprint of a user of electronic data storage card 10 andto generate fingerprint scan data. One example of the fingerprint sensor4 that can be used in the present invention is that disclosed in aco-owned U.S. Pat. No. 6,547,130, entitled “INTEGRATED CIRCUIT CARD WITHFINGERPRINT VERIFICATION CAPABILITY”, the entire disclosure of which isincorporated herein by reference. The fingerprint sensor described inthe above patent includes an array of scan cells that defines afingerprint scanning area. The fingerprint scan data includes aplurality of scan line data obtained by scanning corresponding lines ofarray of scan cells. The lines of array of scan cells are scanned in arow direction as well as column direction of said array. Each of thescan cells generates a first logic signal upon detection of a ridge inthe fingerprint of the holder of card body, and a second logic signalupon detection of a valley in the fingerprint of the holder of cardbody.

The input/output interface circuit 5 is mounted on the card body 1, andis activable so as to establish communication with the external computer9 by way of an optional card reader 12 or via an appropriate socket. Inone embodiment, input/output interface circuit 5 includes circuits andcontrol logic associated with an Universal Serial Bus (USB), PCMCIA orRS232 interface structure that is connectable to an associated socketconnected to or mounted on host computer 9. In another embodiment,input/output interface circuit 5 may include one of a Secure Digital(SD) interface circuit, a Multi-Media Card (MMC) interface circuit, aCompactFlash (CF) interface circuit, a Memory Stick (MS) interfacecircuit, a PCI-Express interface circuit, a Integrated Drive Electronics(IDE) interface circuit, and a Serial Advanced Technology Attachment(SATA) interface circuit, which interface with host computer 9 viaoptional card reader 12 according to known techniques.

The processing unit 2 is mounted on the card body 1, and is connected tothe memory device 3, the fingerprint sensor 4 and the input/outputinterface circuit 5 by way of associated conductive traces or wiresdisposed on card body 1. In one embodiment, processing unit 2 is one ofan 8051, 8052, 80286 microprocessor available, for example, from IntelCorporation. In other embodiments, processing unit 2 includes a RISC,ARM, MIPS or other digital signal processor. In accordance with anaspect of the present invention, processing unit 2 is controlled by aprogram stored at least partially in flash memory device 3 such thatprocessing unit 2 is operable selectively in: (1) a programming mode,where the processing unit 2 activates the input/output interface circuit5 to receive the data file and the fingerprint reference data from thehost computer 9, and to store the data file and the fingerprintreference data in the memory device 3 in a compressed format to increasestorage capacity of the memory device 3; (2) a data retrieving mode,where the processing unit 2 receives the fingerprint scan data from thefingerprint sensor 4, compares the fingerprint scan data with at least asegment of the fingerprint reference data in the memory device 3 toverify if the user of the electronic data storage card is authorized toaccess the data file stored in the memory device 3, and activates theinput/output interface circuit 5 to transmit the data file to the hostcomputer 9 upon verifying that the user of the electronic data storagecard is authorized to access the data file stored in the memory device3; and (3) a data resetting mode, where the data file and the fingerreference data are erased from the memory device 3. In operation, hostcomputer 9 sends write and read requests to electronic data flash card10 via optional card reader 12 and input/output interface circuit 5 tothe processing unit 2, which in turn utilizes a flash memory controller(not shown) to read from or write to the associated one or more flashmemory device 3. In one embodiment, the processing unit 2 automaticallyinitiates operation in the data resetting mode upon detecting that apreset time period has elapsed since storage of the data file and thefingerprint reference data in the memory device 3.

The optional power source 7 is mounted on the card body 1, and isconnected to the processing unit 2 for supplying electrical powerthereto.

The function key set 8, which is mounted on the card body 1, isconnected to the processing unit 2, and is operable so as to initiateoperation of the processing unit 2 in a selected one of the programming,data retrieving and data resetting modes. The function key set 8 isoperable to provide an input password to the processing unit 2. Theprocessing unit 2 compares the input password with the referencepassword in the flash memory device 3, and initiates operation in thedata resetting mode upon verifying that the input password correspondswith the reference password.

The optional display unit 6 is mounted on the card body 1, and isconnected to and controlled by the processing unit 2 for showing thedata file exchanged with the external computer 9 and the operatingstatus of electronic data storage card 10.

As set forth in the specific embodiments below, the present invention isdirected to portable computer peripheral devices that are connected byplug connectors to host computer systems (e.g., computer 9; see FIG. 1)to perform the programming, data retrieving and data resetting functionssimilar to those described above. In particular, as described below withreference to the embodiments shown in FIGS. 2-31, the present inventionis directed to peripheral devices in which a modularUniversal-Serial-Bus (USB) core component 10 is formed that can beinserted into any of a number of different housings, therebyfacilitating the production of a wide range of USB device assemblies inan inexpensive manner. At least some of the components of electronicdata storage card 10 (e.g., card body (PCB) 1, processing unit 2,non-volatile memory device 3 and card reader interface circuit 5) areimplemented in the embodiment described below using USB equivalentcircuits.

FIGS. 2(A) and 2(B) are perspective and cross-sectional side viewsshowing an exemplary modular USB core component 100 that is utilized inthe manufacture of USB assemblies according to the present invention.USB core component 100 generally includes a printed circuit boardassembly (PCBA) 110 and a plastic housing 150 that is molded onto PCBA110. Referring to the upper portion of FIG. 2(A), PCBA 110 includes aprinted circuit board (PCB) 111 including a PCB handle section 112 at arear end of PCB 111, and a PCB plug section 114 at a front end of PCB111. PCB 111 is a substantially flat substrate, and has opposing sidesthat are referred to below as upper (first) surface 116 and lower(second) surface 118. Formed on upper surface 116 in plug section 114are four metal contacts 120. Metal contacts 120 are shaped and arrangedin a pattern established by the USB specification. PCB 111 is formed inaccordance with known PCB manufacturing techniques such that metalcontacts 120, IC dies 130 and 135, and passive components 142, 144 and146 are electrically interconnected by a predefined network includingconductive traces 131 and 136 and other conducting structures that aresandwiched between multiple layers of an insulating material (e.g., FR4)and adhesive.

According to an aspect of the invention, passive components are mountedonto lower surface 118 using one or more standard surface mounttechnology (SMT) techniques, and one or more integrated circuit (IC) die(e.g., control IC die 130 and flash memory die 135) are mounted usingchip-on-board (COB) techniques. As indicated in FIG. 2(B), during theSMT process, the passive components, such as capacitors 142, oscillator144 and a light emitting diode 146, are mounted onto contact pads(described below) disposed on lower surface 118, and are then secured tothe contact pads using known solder reflow techniques. To facilitate theSMT process, each of the passive components is packaged in any of themultiple known (preferably lead-free) SMT packages (e.g., ball gridarray (BGA) or thin small outline package (TSOP)). In contrast, IC dies130 and 135 are unpackaged, semiconductor “chips” that are mounted ontosurface 118 and electrically connected to corresponding contact padsusing known COB techniques. For example, as indicated in FIG. 2(B),control IC die 130 is electrically connected to PCB 111 by way of wirebonds 160-1 that are formed using known techniques. Similarly, flashmemory IC die 135 is electrically connected to PCB 111 by way of wirebonds 160-2. Passive components 142, 144, 146, IC dies 130 and 135 andmetal contacts 120 are operably interconnected by way of metal traces131 and 136 that are formed on and in PCB 111 using known techniques, afew of which being depicted in FIG. 2(A) in a simplified manner by shortdashed lines.

Housing 150 comprises molded plastic arranged such that substantiallyall of the plastic used to form housing 150 is located below (i.e., onone side of) PCB 111. Housing 150 includes a peripheral surface 151extending downward (i.e., perpendicular to PCB 111), and a lower surface152 that extends parallel to PCB 111. For discussion purposes, theportion of peripheral surface 151 surrounding handle section 112 of PCB111 is referred to below as handle surface section 151-1, and thesection of peripheral surface 151 surrounding plug section 114 of PCB111 is referred to below as plug surface section 151-2. Similarly, theportion of lower surface 152 covering handle section 112 of PCB 111 isreferred to below as handle surface section 152-1, and the section oflower surface 152 covering plug section 114 of PCB 111 is referred tobelow as plug cover section 152-2.

Referring again to FIG. 2(A), a handle structure 102 of USB corecomponent 100 is defined by handle surface section 151-1, handle surfacesection 152-1, and the exposed upper surface 116 of PCB handle section112. Similarly, a plug structure 105 of Modular USB core component 100is defined by plug surface section 151-2, plug surface section 152-2,and the exposed upper surface 116 of PCB plug section 114.

Referring to FIGS. 2(A) and 2(B), a thickness T1 and width W1 of plugstructure 105 is selected to produce a secure (snug) fit inside the plugportion of an external case (discussed below).

As indicated in FIG. 2(B), according to another aspect of the presentinvention, housing 150 includes a planar surface 152 that is parallel toPCB 111, and defines a single plane such that a first thickness T1 ofplug structure 105 (i.e., measured between upper PCB surface 116 andplanar surface 152 adjacent to metal contacts 120) is substantiallyequal to a second thickness T2 of handle section 102 (i.e., measuredbetween upper PCB surface 116 and planar surface 152 adjacent to IC 135.That is, as indicated in FIG. 2(B), modular USB core component 100 issubstantially flat along its entire length (i.e., from rear edge 151-1Ato front edge 151-1B). The term “substantially flat” is meant toindicate that planar surface 152 is substantially parallel to anuppermost surface of modular USB core component 100 along its entirelength. In the embodiment shown in FIGS. 2(A) and 2(B), the uppermostsurface of modular USB core component 100 is defined in part by uppersurface 116 of PCB 111, which is parallel to planar surface 152 alongthe entire length of USB core component 100. Similarly, the term“substantially flat” is also intended to cover embodiments describedbelow in which the housing includes a thin wall structure that is formedon or otherwise contacts the upper surface of the PCB. In theseembodiments, the thickness T2 of handle structure 102 may differ by asmall amount (e.g., 5% from thickness T1 of plug structure 105.

According to an aspect of the present invention, the “flatness”associated with modular USB core component 100 is achieved by mountingall of the IC dies (“chips”) and other electronic components of modularUSB core component 100 on lower surface 118 of PCB 111 (i.e., on theside opposite to metal contacts 120). That is, the minimum overallthickness of modular USB core component 100 is determined by thethickness T1 that is required to maintain a snug connection between plugstructure 105 and female USB socket connector (not shown). Because thisarrangement requires that metal contacts 120 be located at the uppermostsurface, and that plug wall section 151-2 plug and cover section 152-2extend a predetermined distance below PCB 111 to provide the requiredthickness T1. Thus, the overall thickness of modular USB core component100 can be minimized by mounting the IC dies 130 and 135 and passivecomponents (e.g., capacitor 142) only on lower surface 118 of PCB 111.That is, if the IC dies and passive components are mounted on uppersurface 116, then the overall thickness of the resulting USB structurewould be the required thickness T1 plus the thickness that the ICsextend above PCB 111 (plus the thickness of a protective wall, if used).

According to another aspect associated with the embodiment shown inFIGS. 2(A) and 2(B), upper surface 116 of PCB 111 is entirely exposed onthe upper surface of modular USB core component 100, thus facilitatingthe production of USB core component 100 with a maximum thickness equalto thickness T1 of plug structure 105. That is, because metal contacts120 are formed on upper surface 116, and upper surface 116 defines thehigher end of required plug structure thickness T1, the overall heightof modular USB core component 100 can be minimized by exposing uppersurface 116 (i.e., by making any point on upper PCB surface 116 theuppermost point of modular USB core component 100). As indicated in FIG.2(A), in accordance with feature specifically associated with modularUSB core component 100, peripheral wall 151 extends around and coversthe peripheral side edges of PCB 111, and an upper edge of peripheralwall 151 is coplanar with upper surface 116 of PCB 111. By covering theperipheral side edge of PCB 111, peripheral wall 151 prevents objectsfrom wedging between PCB 111 and housing 150, thereby preventingundesirable separation of PCBA 110 from housing 150.

FIG. 3 is a flow diagram showing a method for producing modular USB corecomponent 100 according to another embodiment of the present invention.Summarizing the novel method, a PCB panel is generated using knowntechniques (block 210), passive components are mounted on the PCB panelusing SMT techniques (block 220), and the IC dies are die bonded (block246) and wire bonded (block 248) using known COB techniques. Moltenplastic is then used to form a molded housing over the passivecomponents and the IC dies (block 250). Then PCB panel is thensingulated (cut) in to separate USB devices (block 260), the individualUSB devices are marked (block 270), and then the USB devices are tested,packed and shipped (block 280) according to customary practices. Thismethod provides several advantages over conventional manufacturingmethods that utilize SMT techniques only. First, by utilizing COBtechniques to mount the USB controller and flash memory, the largeamount of space typically taken up by these devices is dramaticallyreduced, thereby facilitating significant miniaturization of theresulting USB device footprint. Second, by implementing the wafergrinding methods described below, the die height is greatly reduced,thereby facilitating stacked memory arrangements such as those describedbelow with reference to FIG. 18. The molded housing also providesgreater moisture and water resistance and higher impact force resistancethan that achieved using conventional manufacturing methods. Incomparison to the standard USB memory card manufacturing that used SMTprocess, it is cheaper to use the combined COB and SMT (plus molding)processes described herein because, in the SMT-only manufacturingprocess, the bill of materials such as Flash memory and the Controllerchip are also manufactured by COB process, so all the COB costs arealready factored into the packaged memory chip and controller chip.Therefore, the combined COB and SMT method according to the presentinvention provides a less expensive and higher quality (i.e., morereliable) memory product with a smaller size than that possible usingconventional SMT-only manufacturing methods.

The flow diagram of FIG. 3 will now be described in additional detailbelow with reference to FIGS. 4(A) to 17(B).

Referring to the upper portion of FIG. 3, the manufacturing methodbegins with filling a bill of materials including producing/procuringPCB panels (block 210), producing/procuring passive (discrete)components (block 212) such as resistors, capacitors, diodes, LEDs andoscillators that are packaged for SMT processing, andproducing/procuring a supply of IC wafers (or individual IC dies).

FIGS. 4(A) and 4(B) are top and bottom perspective views, respectively,showing a PCB panel 300(t0) provided in block 210 of FIG. 3 according toa specific embodiment of the present invention. The suffix “tx” isutilized herein to designated the state of the PCB panel during themanufacturing process, with “t0” designating an initial state.Sequentially higher numbered prefixes (e.g., “t1”, “t2” and “t3”)indicate that PCB panel 300 has undergone additional processing.

As indicated in FIGS. 4(A) and 4(B), PCB panel 300(t0) includes atwo-by-nine matrix of regions designated as PCBs 111, each having thefeatures described above with reference to FIGS. 1(A) and 1(B). FIG.4(A) shows upper surface 116 of each PCB 111 (e.g., upper surface 116 ofpanel 111-1 includes metal contacts 120), and FIG. 4(B) shows lowersurface 118 of each PCB 111. Note that lower surface 118 of each PCB 111(e.g., PCB 111-1) includes multiple contact pads 119 arranged inpredetermined patterns for facilitating SMT and COB processes, asdescribed below.

As indicated in FIG. 4(A), in addition to the two rows of PCBs 111,panel 300(t0) includes end border regions 310 and side border regions320 that surround the PCBs 111, and a central region 340 disposedbetween the two rows of PCBs 111. Designated cut lines are scored orotherwise partially cut into PCB panel 300(t0) along the borders of eachof these regions, but do not pass through the panel material. Forexample, end cut lines 311 separate end border panels 310 fromassociated PCBs 111, side cut lines 321 separate side border panels 310from associated PCBs 111, and central cut lines 341 separate centralregion 340 from associated PCBs 111. PCB cut lines 331 are formed alongthe side edges between adjacent PCBs 111. The border panels are providedwith positioning holes and other features known to those skilled in theart to facilitate the manufacturing process, and are removed duringsingulation (described below).

Note that PCBs for USB devices that are produced using SMT-onlymanufacturing processes must be significantly wider than PCBs 111 due tothe space required to mount already packaged flash memory devices. Assuch, PCB panels for SMT-only manufacturing methods typically includeonly twelve PCBs arranged in a 2×6 matrix. By utilizing COB methods tomount the flash memory, the present invention facilitates significantlynarrower PCB 111, thereby allowing each PCB panel 300(t0) to include 18PCBs 111 arranged in a 2×9 matrix. By increasing the number of PCBs 111per PCB panel, the present invention provides shorter manufacturing timeand hence lower cost.

FIG. 5 is a perspective view depicting a portion of a SMT process thatis used to mount passive components on PCB 111-1 according to block 220of FIG. 3. During the first stage of the SMT process, lead-free solderpaste is printed on contact pads 119-1, 119-2 and 119-3, which in thepresent example correspond to SMT components 142, 144 and 146, usingcustom made stencil that is tailored to the design and layout of PCB111-1. After dispensing the solder paste, the panel is conveyed to aconventional pick-and-place machine that mounts SMT components 142, 144and 146 onto contact pads 119-1, 119-2 and 119-3, respectively,according to known techniques. Upon completion of the pick-and-placecomponent mounting process, the PCB panel is then passed through anIR-reflow oven set at the correct temperature profile. The solder ofeach pad on the PC board is fully melted during the peak temperaturezone of the oven, and this melted solder connects all pins of thepassive components to the finger pads of the PC board. FIG. 6 shows theresulting sub-assembled PCB panel 300(t1), in which each PCB 111 (e.g.,PCB 111-1) includes passive components 142, 144 and 146 mounted thereonby the completed SMT process.

FIG. 7 is a simplified perspective view showing a semiconductor wafer400(t0) procured or fabricated according to block 214 of FIG. 3. Wafer400(t0) includes multiple ICs 430 that are formed in accordance withknown photolithographic fabrication (e.g., CMOS) techniques on asemiconductor base 401. In the example described below, wafer 400(t1)includes ICs 430 that comprise USB controller circuits. In a relatedprocedure, a wafer (not shown) similar to wafer 400(t1) isproduced/procured that includes flash memory circuits, and in analternative embodiment (described in additional detail below), ICs 430may include both USB controller circuits and flash memory circuits. Ineach instance, these wafers are processed as described herein withreference to FIGS. 8(A), 8(B) and 8(C).

As indicated in FIGS. 8(A) and 8(B), during a wafer back grind processaccording to block 242 of FIG. 3, base 401 is subjected to a grindingprocess in order to reduce the overall initial thickness TW1 of each IC430. Wafer 400(t1) is first mount face down on sticky tape (i.e., suchthat base layer 401(t0) faces away from the tape), which is pre-taped ona metal or plastic ring frame (not shown). The ring-frame/wafer assemblyis then loaded onto a vacuum chuck (not shown) having a very level, flatsurface, and has diameter larger than that of wafer 400(t0). The baselayer is then subjected to grinding until, as indicated in FIG. 8(B),wafer 400(t1) has a pre-programmed thickness TW2 that is less thaninitial thickness TW1 (shown in FIG. 8(A)). The wafer is cleaned usingde-ionized (DI) water during the process, and wafer 400(t1) is subjectedto a flush clean with more DI water at the end of mechanical grindingprocess, followed by spinning at high speed to air dry wafer 400(t1).

Next, as shown in FIG. 8(C), the wafer is diced (cut apart) alongpredefined border regions separating ICs 430 in order to produce IC dies130 according to block 244 of FIG. 3. After the back grind process hascompleted, the sticky tape at the front side of wafer 400(t1) isremoved, and wafer 400(t1) is mounted onto another ring frame havingsticky tape provided thereon, this time with the backside of the newlygrinded wafer contacting the tape. The ring framed wafers are thenloaded into a die saw machine. The die saw machine is pre-programmedwith the correct die size information, X-axis and Y-axis scribe lanes'width, wafer thickness and intended over cut depth. A proper saw bladewidth is then selected based on the widths of the XY scribe lanes. Thecutting process begins dicing the first lane of the X-axis of the wafer.De-ionized wafer is flushing at the proper angle and pressure around theblade and wafer contact point to wash and sweep away the silicon sawdust while the saw is spinning and moving along the scribe lane. Thesawing process will index to the second lane according to the die sizeand scribe width distance. After all the X-axis lanes have beencompleted sawing, the wafer chuck with rotate 90 degree to align theY-axis scribe lanes to be cut. The cutting motion repeated until all thescribe lanes on the Y-axis have been completed.

FIG. 9 is a perspective view depicting a die bonding process utilized tomount the controller IC dies 130 of FIG. 8(C) and flash memory IC dies135 on PCB 111-1 of the PCB panel according to block 246 of FIG. 3. Thedie bonding process is performed on PCB panel 300(t1) (see FIG. 6), thatis, after completion of the SMT process. The die bonding processgenerally involves mounting controller IC dies 130 into lower surfaceregion 118A, which is surrounded by contact pads 119-5, and mountingflash IC dies 135 into lower surface region 118B, which is disposedbetween rows of contact pads 119-6. In one specific embodiment, anoperator loads IC dies 130 and 135 onto a die bonder machine accordingto known techniques. The operator also loads multiple PCB panels 300(t1)onto the magazine rack of the die bonder machine. The die bonder machinepicks the first PCB panel 300(t1) from the bottom stack of the magazineand transports the selected PCB panel from the conveyor track to the diebond (DB) epoxy dispensing target area. The magazine lowers a notchautomatically to get ready for the machine to pick up the second piece(the new bottom piece) in the next cycle of die bond operation. At thedie bond epoxy dispensing target area, the machine automaticallydispenses DB epoxy, using pre-programmed write pattern and speed withthe correct nozzle size, onto the target areas 118A and 118B of each ofthe PCB 111 of PCB panel 300(t1). When all PCBs 111 have completed thisepoxy dispensing process, the PCB panel is conveyed to a die bond (DB)target area. Meanwhile, at the input stage, the magazine is loading asecond PCB panel to this vacant DB epoxy dispensing target area. At thedie bond target area, the pick up arm mechanism and collet (suction headwith rectangular ring at the perimeter so that vacuum from the centercan create a suction force) picks up an IC die 130 and bonds it ontoarea 118A, where epoxy has already dispensed for the bonding purpose,and this process is then performed to place IC die 135 into region 118B.Once all the PCB boards 111 on the PCB panel have completed die bondingprocess, the PCB panel is then conveyed to a snap cure region, where thePCB panel passes through a chamber having a heating element thatradiates heat having a temperature that is suitable to thermally curethe epoxy. After curing, the PCB panel is conveyed into the empty slotof the magazine waiting at the output rack of the die bonding machine.The magazine moves up one slot after receiving a new panel to get readyfor accepting the next panel in the second cycle of process. The diebonding machine will repeat these steps until all of the PCB panels inthe input magazine are processed. This process step may repeat again forthe same panel for stack die products that may require to stacks morethan one layer of memory die. FIG. 10 is a top perspective views showingPCB panel 300(t2) after the die bonding process is completed.

FIG. 11 is a perspective view depicting a wire bonding process utilizedto connect the IC dies 130 and 135 to corresponding contact pads 119-5and 119-6, respectively, according to block 248 of FIG. 3. The wirebonding process proceeds as follows. Once a full magazine of PCB panels300(t2) (see FIG. 10) has completed the die bonding operation, anoperator transports the PCB panels 300(t2) to a nearby wire bonder (WB)machine, and loads the PCB panels 300(t2) onto the magazine input rackof the WB machine. The WB machine is pre-prepared with the correctprogram to process this specific USB device. The coordinates of all theICs' pads 119-5 and 119-6 and PCB gold fingers were previouslydetermined and programmed on the WB machine. After the PCB panel withthe attached dies is loaded at the WB bonding area, the operatorcommands the WB machine to use optical vision to recognize the locationof the first wire bond pin of the first memory die of the first PCB onthe panel. Once the first pin is set correctly, the WB machine can carryout the whole wire bonding process for the rest of the panels of thesame product type automatically. For multiple flash layer stack dies,the PCB panels may be returned to the WB machine to repeat wire bondingprocess for the second stack. FIG. 12 is a top perspective views showingPCB panel 300(t3) after the wire bonding process is completed.

FIGS. 13(A) and 13(B) are simplified cross-sectional side viewsdepicting a molding process for forming a molded housing layer over PCBpanel 300(t3) according to block 250 of FIG. 3. As indicated in FIG.13(A), after the wire bonding process is completed, USB panel 300(t3) isloaded into a mold machine 450 including a cover plate 452 that mountsonto lower surface 116 of PCB panel 300(t3), and defines a chamber 456that is disposed over the IC chips, wire bonds and passive componentsthat are mounted on lower surface 116. Note that no molding material isapplied to upper surface 118. Transfer molding is prefer here due to thehigh accuracy of transfer molding tooling and low cycle time. Themolding material in the form of pellet is preheated and loaded into apot or chamber (not shown). As depicted in FIG. 13(B), a plunger (notshown) is then used to force the material from the pot through channelsknown as a spruce and runner system into the mold cavity 456, causingthe molten (e.g., plastic) material to form a molding layer 458 thatencapsulates all the IC chips and components, and to cover all theexposed areas of lower surface 116. The mold remains closed as thematerial is inserted and filled up all vacant in cavity 456. During theprocess, the walls of cover plate 452 are heated to a temperature abovethe melting point of the mold material, which facilitates a faster flowof material through cavity 456. Mold machine 450 remains closed until acuring reaction within the molding material is complete. A cooling downcycle follows the injection process, and the molding materials ofmolding layer 458 start to solidify and harden. Ejector pins push PCBpanel 300(t4) (shown in FIG. 14) from the mold machine once moldinglayer 458 has hardened sufficiently. As depicted in FIG. 14, moldinglayer 458 forms a uniform block with a flat, smooth upper surface 459 onPCB panel 300(t4).

FIG. 15 is simplified cross-sectional side view depicting a singulationprocess according to block 260 of FIG. 3 that is used to separate PCBpanel 300(t4) into individual USB devices. PCB panel 300(t4) is loadedinto a saw machine (not shown) that is pre-programmed with a singulationroutine that includes predetermined cut locations. The saw blade isaligned to the first cut line (e.g., end cut line 311-1) as a startingpoint by the operator. The coordinates of the first position are storedin the memory of the saw machine. The saw machine then automaticallyproceeds to cut up (singulate) the USB pane 300(t4), for example,successively along cut lines 311-1, 341-1, 341-2, and 311-2, and thenalong the side cut lines and PCB cut lines (see FIG. 4(A)) to formindividual USB devices according to the pre-programmed singulationroutine. FIGS. 16(A) and 16(B) are top and bottom perspective viewsshowing a modular USB core component 100 after the singulation processis completed.

FIGS. 17(A) and 17(B) are top and bottom perspective views showing asingulated modular USB core component 100 after a marking process isperformed in accordance with block 270 of the method of FIG. 3. Thesingulated and completed USB devices 100 undergo a marking process inwhich a designated company's logo, USB logo, RoHs logo, speed value,density value, or other related information are printed on surface 152of housing 150 and/or upper surface 116 of PCB 111. After marking, USBdevices 100 are placed in the baking oven to cure the permanent ink.

Referring to block 280 located at the bottom of FIG. 3, a finalprocedure in the manufacturing method of the present invention involvestesting, packing and shipping the individual USB devices. The marked USBdevices 100 shown in FIGS. 17(A) and 17(B) are then subjected to visualinspection and electrical tests consistent with well establishedtechniques. Visually or/and electrically test rejects are removed fromthe good population as defective rejects. The good memory cards are thenpacked into custom made boxes which are specified by customers. Thefinal packed products will ship out to customers following correctprocedures with necessary documents.

As suggested in the above example, in addition to reducing overallmanufacturing costs by utilizing unpackaged controller and flash memorydies (i.e., by eliminating the packaging costs associated with SMT-readycontroller and flash memory devices), the present invention provides afurther benefit of facilitating greatly expanded memory capacity withoutincreasing the overall size of modular USB core component 100. Forexample, FIG. 18 is simplified cross-sectional side view showing astacked-memory USB device 500 in which a first flash memory chip 535-1is mounted on a lower surface 518 and connected by first wire bonds560-1 to PCB 511 in the manner described above. Because the IC dieheight (thickness) D is much smaller than packaged flash memory devices,and because the thickness T1 of USB device 500 is set, for example, at2.0 mm to assure a snug fit of plug structure 105 inside the lowerregion of a standard female USB socket connector, the present inventionfacilitates a stacked memory arrangement in which a second flash memorydie 535-2 is mounted on first flash memory die 535-1 and connected toPCB 511 by way of second wire bonds 560-2. In an alternative embodiment(not shown), second flash memory die 535-2 may be connected to contactsprovided on first flash memory die 535-1 by associated wire bonds. Thisstacked memory arrangement greatly increases memory capacity of the USBdevices without increasing the footprint (i.e., thickness T1, length andwidth) of modular USB core component 500.

FIG. 19 is simplified cross-sectional side view showing a modular USBcore component 600 including stacked-memory according to anotherembodiment of the present invention. Modular USB core component 600 isdistinguished over the previous embodiments in that, instead of separateUSB controller and flash memory chips, USB device 600 utilizes asingle-chip controller/flash die 630 that is connected to a PCB 610 byway of wire bonds 660 in the manner described above, and ischaracterized in that, as shown in FIG. 20, single-chip controller/flashdie 630 includes both a controller circuit 631 and one or more flashblock mass storage circuits 635-1 to 635-3 that are interconnected by abus 638. Controller circuit 631 includes an input/output (I/O) interfacecircuit 632 that facilitates sending and receiving commands and datato/from a host (not shown) into which USB device 600 is plugged.Controller circuit 631 also includes a flash-memory controller 634 thatfacilitates sending and receiving sends data over one or more internalflash buses 638 to/from flash mass storage blocks 635-1, 635-2, 635-3.Because internal flash bus 638 is internal to single-chipcontroller/flash die 630, external pins are not required for theinterface to flash memory blocks 635-1, 635-2, 635-3. In one embodiment,flash mass storage blocks 635-1, 635-2, 635-3 are not randomlyaccessible. Instead, a command and an address are transferred as dataover internal flash bus 638 to indicate a block of data to transfer fromflash mass storage blocks 635-1, 635-2, 635-3. Thus, flash mass storageblocks 635-1, 635-2, 635-3 are block-addressable mass storage, ratherthan random-access memory (RAM). In another embodiment, flash massstorage blocks 635-1, 635-2, 635-3 are aggregated together by the flashmicrocontroller of controller circuit 631, which maps and directs datatransactions to selected flash storage blocks 635-1, 635-2, 635-3.Because the flash microcontroller 631 performs memory management, flashstorage blocks 635-1, 635-2, 635-3 appear as a single, contiguous memoryto external hosts. Additional details regarding the use of single-chipcontroller/flash die 630 is provided in co-owned U.S. Pat. No.7,103,684, which is incorporated herein by reference in its entirety.

In accordance with another aspect of the present invention, the modularUSB core components described in the embodiments above are pivotablyincorporated into swivel housings (cases) in order to form completedswivel-type USB assemblies (i.e., USB devices suitable for sale to anend user) in which the swivel housings protect the metal contacts fromcontamination or damage (e.g., scratches) when the USB assembly is notin use, and facilitates deploying the plug end of the modular core USBcomponent using a thumb or finger when use is desired. Several examplesof such swivel-type USB assemblies are described in the followingparagraphs. In addition, different package assembly methods aredescribed in which the modular USB core component is pivotably mountedor otherwise disposed inside a swivel housing to produce a final memorycard product. For brevity, a generalized modular USB core component 100is used in the following examples and represents any of the embodimentsdescribed above.

FIG. 21 is an exploded perspective view showing a swivel-cover USBassembly 700 according to a first specific embodiment that includes amovable holder 710 for supporting modular USB core component 100, anexternal housing 730, and a pivot pin 740. FIGS. 22(A) and 22(B) are topperspective views showing USB assembly 700 in a closed (retracted)position and an opened (deployed) position, respectively. As shown inthese figures and described in greater detail below, modular USB corecomponent 100 is fixedly attached to holder 710, and then thesubassembly is inserted into a gap 732 between walls 731A and 731B ofexternal housing 730. The subassembly and housing 730 are then connectedby way of pivot pin 740, which is inserted through a hole 717 formed inflange 715 of holder 710 and through a pivot opening 737 defined inexternal housing 730. Thus connected, as indicated in FIGS. 22(A) and22(B), holder 710 is pivotable (rotatable) around an axis X defined inthe center of pivot pin 740 between a closed position (see FIG. 22(A))in which holder 710 is disposed in gap 732 between walls 731A and 731Bsuch that the metal contacts of modular USB core component 100 areprotected by a region 731B1 of upper wall 731B, and an open position(see FIG. 22(B)) in which holder 710 is disposed outside of housing 730such that metal contacts 120 of modular USB core component 100 areaccessible by a data terminal (not shown).

FIGS. 23(A) and 23(B) are exploded perspective and assembled perspectiveviews showing a sub-assembly 700A including modular USB core component100, holder 710, and an adhesive layer (e.g., a double-sidedself-adhesive tape) 720 for adhering modular USB core component 100 ontoholder 710 according to an embodiment of the present invention.

Referring to the lower portion of FIG. 23(A) holder 710 has a lower wall711 that is surrounded by peripheral walls (i.e., opposing side walls713-1 and 713-2, a rear wall 714-1 and a front wall 714-2), therebyforming a trough 712 for receiving modular USB core component 100.Holder 710 also includes a flange 715 having side portions 716-1 and716-2 formed with multiple fine ribs for improving frictional forcebetween a user's fingers to facilitate pivoting holder 710 between theopen and closed positions (see FIGS. 22(A) and 22(B)). Circular throughhole 717 is defined through flange 715, and includes one or moreprotrusions 718 formed on an inside surface thereof for engaging withpivot pin 740 (see FIG. 21). In one embodiment holder 710 is asingle-piece, pre-molded plastic structure formed using a suitableplastic. The term “pre-molded” is used herein to indicate that holder710 is an integral molded structure formed during a separate (e.g.,injection) plastic molding process that is performed prior to assembly.

As indicated by the dashed-line arrows in FIG. 23(A), the assemblyprocess for producing sub-assembly 700A involves taping modular USB corecomponent 100 into trough 712 of holder 710 by placing double sidedadhesive tape 720 on lower wall 711, and then inserting modular USB corecomponent 100 into trough 712 with metal contacts 120 facing upward. Asindicated in FIG. 23(B), trough 712 is sized such that the peripheralwalls fit tightly around the peripheral edge of modular USB corecomponent 100 (i.e., with minimal gap), and such that an upper surfaceof the peripheral walls of holder 710 are flush with or slightly higherthan an upper surface of modular USB core component 100.

FIG. 24 is an exploded view showing a process of attaching sub-assembly700A to external (swivel) housing 730 using pivot pin 740 to form USBassembly 700.

Housing 730 is either a pre-molded plastic structure or a metalstructure formed using a die-casting process and plated with a brightchromium coating to provide a bright and shiny surface appearance.Housing 730 includes lower wall 731A and upper wall 731B that are heldin a substantially parallel relationship by an end wall 734 such thatgap 732 is defined between lower wall 731A and upper wall 731B. Pivotopening 737 is defined in upper wall 731B adjacent to the end oppositeend wall 734, and includes notches 738 whose purpose is described below.in one embodiment a similar opening (not shown) is defined in lower wall731A. A circular key chain structure 739 is integrally formed on endwall 734 to receive a string or chain to form a key holder, or simplyfor users to hang tiny ornaments for decoration.

As indicated by the dashed-line arrows in FIG. 24, sub-assembly 700A isinserted between lower wall 731A and upper wall 731B positioned suchthat through hole 717 of holder 710 aligns with pivot opening 737 formedin upper wall 731B of housing 730, and then pivot pin 740 is insertedthrough pivot opening 737 and through hole 717 to complete USB assembly700. As shown in FIG. 25, pivot pin 740 has a substantially cylindricalbase section 741 including grooves 742 for engaging with protrusions 718of holder 710 (see FIG. 24), a raised section 743, and two curved arms745 that extend from raised section 743 and include protruding bumps 748that engage with notches 738 formed in upper wall 731B of housing 730when USB assembly 700 is either in the open position (see FIG. 22(B)) orthe closed position (see FIG. 22(A)). FIGS. 26(A) and 26(B) are partialtop views showing pivot pin 740 after insertion into pivot opening 737,with FIG. 26(A) showing the positional relationship between pivot pin740 and pivot opening 737 in the opened or closed positions, and FIG.26(B) showing the positional relationship between pivot pin 740 andpivot opening 737 during a transition between the opened or closedpositions. As indicated in FIG. 26(A), when USB assembly 700 is eitherfully opened (as shown in FIG. 22(B)) or fully closed (as shown in FIG.22(A)), protruding bumps 748 are resiliently biased into notches 738 bycurved arms 745, thereby “locking” the holder to the housing in eitherthe opened or closed position. As shown in FIG. 26(B), when it isdesired to open (or close) the assembly, a user manually applies arotating force to the assembly so as to pivot holder relative to thehousing around axis X. When the applied rotational force is strongenough to overcome the resistance produced by the engagement betweenprotruding bumps 748 and notches 738, curved arms 745 deflect inward(i.e., in the direction of the curved dashed-line arrows in FIG. 26(B),whereby protruding bumps 748 are withdrawn from notches 738 and ridealong the circular inner surface of pivot opening 737. When theopening/closing operation is completed, protruding bumps 748 are againengaged into notches 738 to “lock” the holder into the desired positionrelative to the housing.

FIG. 27 shows an optional manufacturing stage in which USB assembly 700is further processed to respectively adhere cover plates 750A and 750Bto lower wall 731A and upper wall 731B of housing 730, thereby forming amodified USB assembly 700B. Cover plates 750A and 750B are made ofeither plastic or metal, and are secured by way of a suitable adhesivethat is applied so that cover plates 750A and 750B are not adhered tothe ends of pivot pins 740 (i.e., such that pivot pins 740 rotate freelyunder cover plates 750A and 750B). FIGS. 28(A) and 28(B) show themodified USB assembly 700B in the closed position and in the openposition, respectively. Note that cover plate 750B covers upper wall731B such that the pivot pin is not in view, thereby providing a moreappealing package. Further, cover plates 750A and 750B serve to maintainthe connection of the pivot pin inside USB assembly 700 duringactuation.

FIGS. 29(A) and 29(B) are exploded perspective and assembled perspectiveviews showing a sub-assembly 800A according to a second specificembodiment of the present invention. Sub-assembly 800A includes modularUSB core component 100, a holder 810, and an adhesive layer (e.g., adouble-sided self-adhesive tape) 820.

Referring to the lower portion of FIG. 29(A), holder 810 has a lowerwall 811 that is surrounded by peripheral walls (i.e., opposing sidewalls 813-1 and 813-2, a rear wall 814-1 and a front wall 814-2),thereby forming a trough 812 for receiving modular USB core component100. Holder 810 also includes a flange 815 having side portions 816-1and 816-2 formed with multiple fine ribs for improving frictional forcebetween a user's fingers to facilitate pivoting holder 810 between theopen and closed positions. A pivot pin structure 840 is integrallymolded onto a platform 841 that is connected to flange 815 by bridgestructures 845 such that air gaps G are formed between peripheral edgesof platform 845 and flange 815, and such that pivot pin 840 is movablein a vertical direction (i.e., in the direction of vertical arrow V)relative to flange 815. Engagement structures 848 are disposed next toand extend radially from pivot pin 840. FIG. 29(B) shows sub-assembly800A after mounting modular USB core component 100 into holder 810.

FIG. 30 is an exploded view showing a process of attaching sub-assembly800A to an external (swivel) housing 830 in order to form USB assembly800. Housing 830 is an elongated plate metal structure that is bent toinclude a 180° end wall 834 connected to a lower wall 831A and an upperwall 831B that are separated by an elongated gap 832. Lower wall 831Aand upper wall 831B are generally parallel, but gap 832 slightly changesfrom a relatively wide height H1 adjacent to end wall 834 to arelatively narrow height H2 adjacent to the free (open) end to providetight tension at the pivoting point. At least one circular opening 837is defined in upper wall 831B, and includes one or more notches 838 thatoperably engage with engagement structure 848 of pivot pin 840 in amanner that “locks” holder 810 to housing 830 in the opened and closedposition in a manner similar to that described above with reference topivot pin 740. The completed USB assembly 800 is shown in FIGS. 31(A)and 31(B). Thus connected, holder 810 is pivotable (rotatable) aroundthe center of pivot pin 740 between a closed position (see FIG. 31(A))in which holder 810 is disposed in gap 832 between walls 831A and 831Bsuch that the metal contacts of modular USB core component 100 areprotected by upper wall 831B, and an open position (see FIG. 31(B)) inwhich holder 810 is disposed outside of housing 830 such that metalcontacts 120 of modular USB core component 100 are accessible by a dataterminal (not shown).

Although the present invention has been described with respect tocertain specific embodiments, it will be clear to those skilled in theart that the inventive features of the present invention are applicableto other embodiments as well, all of which are intended to fall withinthe scope of the present invention.

1. A swivel-type, low-profile USB assembly adapted to be selectivelyaccessed by a data terminal, said USB assembly comprising: a modular USBcore component comprising: a printed circuit board assembly (PCBA)including: a card body, a non-volatile memory device mounted on the cardbody, a card reader interface circuit mounted on said card body, and aprocessing unit mounted on said card body and connected to saidnon-volatile memory device and said card reader interface circuit,wherein said card body comprises a printed circuit board (PCB) havingopposing first and second surfaces, a plurality of metal contactsdisposed on the first surface, at least one passive component mounted onthe second surface, wherein at least one of the non-volatile memorydevice, the card reader interface circuit and the processing unitcomprises an unpackaged integrated circuit (IC) die mounted on thesecond surface of the PCB handle section, and wherein a plurality ofconductive traces are formed on the PCB such that each conductive traceis electrically connected to at least one of an associated metalcontact, the IC die and the passive component; and a single-piece moldedhousing formed on the second surface of the PCBA such that said at leastone passive component and said at least one IC die are covered by saidmolded housing, and such that substantially all of the first surface ofthe PCB is exposed; and an elongated holder including a flange disposedat a first end thereof, wherein the modular USB core component isfixedly connected to the holder such that the metal contacts aredisposed adjacent to a second end thereof; an external housing includingfirst and second walls defining an elongated gap therebetween, whereinthe flange of the holder is connected to the external housing such thatthe holder is pivotable between a closed position in which the holder isdisposed in the gap between the first and second walls of the externalhousing, whereby the metal contacts of the modular USB core componentare protected by a region of the first wall, and an open position inwhich the holder is disposed outside of the external housing such thatmetal contacts of the modular USB core component are accessible by thedata terminal.
 2. The swivel-type, low-profile USB assembly according toclaim 1, wherein said holder includes peripheral walls surrounding atrough, the peripheral walls including a front wall disposed adjacentthe second end, and wherein the modular USB core component is fixedlyreceived in the trough of the holder such that the metal contacts aredisposed adjacent to the front wall.
 3. The swivel-type, low-profile USBassembly of claim 2, wherein the external housing further comprises anend wall connected to first ends of the first and second walls such thatthe first wall is held generally parallel to the second wall with thegap defined therebetween, wherein at least one of the first and secondwalls defines a pivot opening located adjacent to a second end of saidfirst and second walls, and wherein holder is pivotably connected to theexternal housing by a pivot pin rotatably received in the pivot opening.4. The swivel-type, low-profile USB assembly of claim 3, wherein thefirst and second walls of the external housing comprise metal platedwith chromium.
 5. The swivel-type, low-profile USB assembly of claim 3,wherein the external housing comprises a pre-molded plastic structure.6. The swivel-type, low-profile USB assembly of claim 3, furthercomprising a circular key chain structure integrally formed on the endwall.
 7. The swivel-type, low-profile USB assembly of claim 3, whereinthe holder further comprises side portions respectively extendingoutside of the gap when the holder is in either of the opened positionand the closed position, wherein each of the side portions includes aplurality of fine ribs.
 8. The swivel-type, low-profile USB assembly ofclaim 1, wherein the pivot pin comprises a pre-molded plastic structurethat is fixedly connected to the holder and rotatably engaged in thepivot opening.
 9. The swivel-type, low-profile USB assembly of claim 7,wherein the pivot pin includes curved arms having at least one bumpprotruding therefrom, and wherein the curved arms bias said bump toengage one or more corresponding notches defined in a peripheral edge ofthe pivot opening when the holder is in either of the opened positionand the closed position.
 10. The swivel-type, low-profile USB assemblyof claim 3, wherein the pivot pin is integrally connected to and extendsfrom the flange of the holder into the pivot opening defined in thefirst wall of the external housing.
 11. The swivel-type, low-profile USBassembly of claim 10, wherein the pivot pin extends from a platform thatis connected to the flange by bridge structures such that the pivot pinis movable relative to the flange, and engagement structures disposedadjacent to the pivot pin operably engage corresponding notches definedin the first wall of the external housing when the holder is in eitherof the opened position and the closed position.
 12. The swivel-type,low-profile USB assembly of claim 11, wherein the external housingfurther comprises a metal structure and said end wall comprises aportion of said metal structure that is bent 180°, and wherein the firstand second walls are separated by a first height adjacent to the endwall and by a second height adjacent to the flange of the holder, wherethe first height is greater than the second height.
 13. The swivel-type,low-profile USB assembly of claim 1, wherein the at least one integratedcircuit (IC) die is electrically connected to the conductive traces by aplurality of wire bonds extending between said at least one IC die andcorresponding contact pads disposed on the second surface of the PCB.14. The swivel-type, low-profile USB assembly of claim 13, wherein theat least one passive component includes a lead that is soldered to acorresponding contact pad disposed on the second surface of the PCB. 15.The swivel-type, low-profile USB assembly of claim 14, wherein the atleast one passive component comprises at least one of a resistor, acapacitor, an oscillator, and a light emitting diode.
 16. Theswivel-type, low-profile USB assembly of claim 13, wherein the at leastone integrated circuit (IC) die includes a first IC die comprising anUSB controller circuit, and a second IC die comprising a flash memorycircuit.
 17. The swivel-type, low-profile USB assembly of claim 16,wherein the at least one IC die comprises a plurality of flash memorydies disposed in a stacked arrangement such that a first flash memorydie is mounted on the second surface of the PCB, and a second flashmemory die is mounted on a surface of the first flash memory die. 18.The swivel-type, low-profile USB assembly of claim 17, wherein the firstflash memory die is connected to said PCB by a first plurality of saidwire bonds, and the second flash memory die is connected to one of thefirst flash memory die and said PCB by a second plurality of wire bonds.19. The swivel-type, low-profile USB assembly of claim 13, wherein theat least one integrated circuit (IC) die includes a single-chipcontroller/flash die comprising controller circuit and one or more flashblock mass storage circuits that are interconnected by a bus.
 20. Amethod for producing an USB assembly comprising: producing a modular USBcore component including: a PCBA including: a card body, a non-volatilememory device mounted on the card body, a card reader interface circuitmounted on said card body, and a processing unit mounted on said cardbody and connected to said non-volatile memory device and said cardreader interface circuit, wherein said card body comprises a printedcircuit board (PCB) having opposing first and second surfaces, aplurality of metal contacts disposed on the first surface, at least onepassive component mounted on the second surface, wherein at least one ofthe non-volatile memory device, the card reader interface circuit andthe processing unit comprises an unpackaged integrated circuit (IC) diemounted on the second surface of the PCB handle section, and wherein aplurality of conductive traces are formed on the PCB such that eachconductive trace is electrically connected to at least one of anassociated metal contact, the IC die and the passive component; and asingle-piece molded housing formed on the second surface of the PCBAsuch that said at least one passive component and said at least one ICdie are covered by said molded housing, and such that substantially allof the first surface of the PCB is exposed; and; and mounting saidmodular USB core component into a holder having a flange; and attachingthe holder to an external housing including first and second wallsdefining an elongated gap therebetween such that the holder is pivotablebetween a closed position in which the holder is disposed in the gapbetween the first and second walls of the external housing, whereby themetal contacts of the modular USB core component are protected by aregion of the first wall, and an open position in which the holder isdisposed outside of the external housing such that metal contacts of themodular USB core component are accessible by the data terminal.